The problem of electrostatic discharge (ESD) is well known and almost everyone has experienced it while wearing shoes with non-conductive soles, walking across a carpet, for example, and touching a grounded object such as a doorknob. The average consumer's concerns about the comfort in both the home and workplace have never been addressed by either the shoe manufacturers or by any of the other referenced patents. The current invention is primarily to address that need. The present invention will also aid in reducing ESD and accumulation of static electricity in the body and clothing that can also cause clothing to adhere to the body and can cause embarrassment or at least an uncomfortable feeling in the wearer.
Many employers now allow employees to wear their casual shoes to work in a carpeted office environment and as a result there has been a dramatic increase of office workers that are experiencing ESD, which further increases the need to dissipate ESD to eliminate annoying and uncomfortable ESD events.
Rubber soles, and later other man made materials, have been used on many types of shoes for almost 100 years. These soles reduced costs, provide greater traction, provide consistency; as well as good wear characteristics, and moisture resistance. They also provide insulation of the body from a source of an earthly ground. Almost since these soles were adopted by industry, the insulative quality of these soles has been both a problem and in some cases a benefit for the wearer of such footwear.
For the electrician the insulation can be a benefit, but for most users the static electricity that is stored in the wearer's clothes and body by this insulative quality can cause annoying and oftentimes painful electrical shocks when a place on the insulated body touches a grounding source.
Over the years many solutions to the ESD problem have been patented. Most have been primarily intended as industry solutions to the harmful affects that ESD can cause to electronic components. Some such U.S. Pat. Nos. 4,249,226 by Westberg, 5,191,505 by Gordon, 5,184,275 by Wiegel, 5,786,977 by Cohen, 6,307,727 by De Angelis, and 6,707,659 by Hee, are examples of these industry solutions that were acceptable industry solutions but ones that would never be worn in daily life for obvious aesthetic and safety reasons and in practice on common surfaces they would wear out very quickly. Most of these inventions also look uncomfortable to put on and to wear. A person who is a jogger or tennis player would probably be amused at all of the aforementioned inventions and would never consider them for reasons that would be obvious by a visual review of said inventions.
Still another industry solution was to apply a wristband to the person to be grounded, see U.S. Pat. No. 5,018,044 by Weiss as an example, but this solution “leashed” the worker to a very small area and again would not be practical in day-to-day life to control ESD. Again, most of the above solutions were intended as industry solutions for manufacturing concerns in the computer and electronics industries and were not intended for the users comfort or aesthetics of people in their day-to-day life.
Patents such as U.S. Pat. No. 4,785,371 by Edwards and U.S. Pat. No. 5,426,870 by Purnell were developed for the shoe manufacturers to eliminate the ESD problem by modifications to the manufacturing process and materials to facilitate a grounding effect in the shoe itself. These solutions would have been extremely costly to implement and one can presume this is the reason they are not commercially available.
Some inventions such as that disclosed in U.S. Pat. No. 4,727,452 by Brownlee, attempted to provide a grounding path as well as heat dissipation. This device would also be expensive, inflexible and uncomfortable as well as adding difficulty to size for all the various shoe sole thicknesses. Proper installation of this device in a proper location on the shoe may also have been a critical problem. This device also had a hard disk that made contact with the wearer's foot and the earth and substrate. This condition could cause injury to the foot when impacting a foreign object, such as a rock, or during a landing from a jump and could also cause a fall when the hard disk, which does not provide the traction of the otherwise soft sole of the shoe, makes contact with another hard surface such as linoleum or other hard surfaces. Additionally the hard disk in this invention once mounted to the sole of the shoe could mar floor coverings such as wood or vinyl. The aforementioned device also did not provide the resistance that is required to preclude an ESD event when moving from a non-grounded surface to a grounded surface.